We look at the division of 51035315 by 645 
We want to figure out the number of times 51035315 can be divided by 645.

Going ahead to step 1:
645 can be fit into 5 0 times, resulting in a remainder of 5.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 5 after subtracting 0 from 5.
Grab the next digit (1) from the dividend, add it to 5, then carry on: 51 / 645

Advancing to step 2:
645 can be fit into 51 0 times, resulting in a remainder of 51.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 51 leaves us with 51.
Fetch the next digit (0) from the dividend, attach it to 51 and continue: 510 / 645

On to step 3:
The number 645 fits into 510 0 times, leaving a remainder of 510.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 510, we get 510.
Bring next digit (3) of the dividend behind the 510 and repeat the process: 5103 / 645

On to step 4:
The number 645 fits into 5103 7 times, leaving a remainder of 588.
Record the quotient 7 as the next digit in the result. 
Result so far: 7.0
The remainder is 588 after subtracting 4515 from 5103.
Grab the next digit (5) from the dividend, add it to 588, then carry on: 5885 / 645

Step 5:
645 can be fit into 5885 9 times, resulting in a remainder of 80.
Use 9 as the next digit of our solution. 
Result so far: 79.0
If we subtract 5805 from 5885, we get 80.
Include the next digit (3) from the dividend after 80, then repeat: 803 / 645

Advancing to step 6:
803 divided by 645 is 1 with a remainder of 158.
Record the quotient 1 as the next digit in the result. 
Result so far: 791.0
If we subtract 645 from 803, we get 158.
Take the next digit (1) from the dividend and append it to 158, then repeat: 1581 / 645

On to step 7:
If we divide 1581 by 645, we get 2 and a remainder of 291.
The number 2 becomes the next digit in our result. 
Result so far: 7912.0
If we take 1290 away from 1581, we end up with 291.
Take the next digit (5) from the dividend and append it to 291, then repeat: 2915 / 645

On to step 8:
645 can be fit into 2915 4 times, resulting in a remainder of 335.
Put 4 as the next digit of the answer. 
Result so far: 79124.0
Deduct 2580 from 2915 and we're left with 335.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3350, and continue the process.

Step 9:
When dividing 3350 by 645, we get 5 with a remainder of 125.
Record the quotient 5 as the next digit in the result. 
Result so far: 79124.5
If we subtract 3225 from 3350, we get 125.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1250, and continue the process.

Going ahead to step 10:
645 can be fit into 1250 1 times, resulting in a remainder of 605.
Use 1 as the next digit of our solution. 
Result so far: 79124.51
If we subtract 645 from 1250, we get 605.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6050, and continue the process.

Step 11:
6050 divided by 645 is 9 with a remainder of 245.
The next digit of our result is 9. 
Result so far: 79124.519
The remainder is 245 after subtracting 5805 from 6050.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2450, and continue the process.

Step 12:
The number 645 fits into 2450 3 times, leaving a remainder of 515.
Put 3 as the next digit of the answer. 
Result so far: 79124.5193
The remainder is 515 after subtracting 1935 from 2450.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5150, and continue the process.

On to step 13:
The number 645 fits into 5150 7 times, leaving a remainder of 635.
Put 7 as the next digit of the answer. 
Result so far: 79124.51937
The remainder is 635 after subtracting 4515 from 5150.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6350, and continue the process.

Step 14:
645 can be fit into 6350 9 times, resulting in a remainder of 545.
Use 9 as the next digit of our solution. 
Result so far: 79124.519379
If we take 5805 away from 6350, we end up with 545.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5450, and continue the process.

Advancing to step 15:
5450 divided by 645 is 8 with a remainder of 290.
Record the quotient 8 as the next digit in the result. 
Result so far: 79124.5193798
If we take 5160 away from 5450, we end up with 290.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2900, and continue the process.

Moving on to step 16:
645 goes into 2900 4 times with a remainder of 320.
Put 4 as the next digit of the answer. 
Result so far: 79124.51937984
Subtract 2580 from 2900 to get 320.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3200, and continue the process.

Our division results in 79124.51937984 with a remaining 3.2e-07.